This struck me as a surprisingly substantive debate - not just compared to the Republican debates, a low bar, but the earlier Democratic one too. A hard hitting and spirited exchange on national security and ISIS, with some real digging into the backstory of the invasion of Iraq, the final withdrawal of American troops, etc. Then a similar exchange on banks and the financial sector - though someone explaining what Glass–Steagall was might have helped. The fact that the debate about whether commercial banks should also do investment banking still goes under the rubric of a 30s era piece of legislation tells you a lot about the difference between Democratic and Republican politics.
As I said, there was less focus and intensity as the debate moved on to policing, Black Lives Matter, health care, etc. I think that's because the divisions simply aren't as clear. Secondarily, the candidates seemed to draw back from the intensity of the first hour. On balance, I'd say it's a win for Hillary Clinton - not because she necessarily did better than Sanders but because she's now ahead and I did not see anything happen that looks likely to change that dynamic.